Struct gstreamer::structure::Structure

pub struct Structure(/* private fields */);

A Structure is a collection of key/value pairs. The keys are expressed as GQuarks and the values can be of any GType.

In addition to the key/value pairs, a Structure also has a name. The name starts with a letter and can be filled by letters, numbers and any of “/-_.:”.

Structure is used by various GStreamer subsystems to store information in a flexible and extensible way. A Structure does not have a refcount because it usually is part of a higher level object such as Caps, Message, Event, Query. It provides a means to enforce mutability using the refcount of the parent with the gst_structure_set_parent_refcount() method.

A Structure can be created with new_empty() or [new()][Self::new()], which both take a name and an optional set of key/value pairs along with the types of the values.

Field values can be changed with gst_structure_set_value() or gst_structure_set().

Field values can be retrieved with gst_structure_get_value() or the more convenient gst_structure_get_*() functions.

Fields can be removed with gst_structure_remove_field() or gst_structure_remove_fields().

Strings in structures must be ASCII or UTF-8 encoded. Other encodings are not allowed. Strings may be None however.

The serialization format

GstStructure serialization format serialize the GstStructure name, keys/GType/values in a comma separated list with the structure name as first field without value followed by separated key/value pairs in the form key=value, for example:

a-structure, key=value

The values type will be inferred if not explicitly specified with the (GTypeName)value syntax, for example the following struct will have one field called ‘is-string’ which has the string ‘true’ as a value:

a-struct, field-is-string=(string)true, field-is-boolean=true

Note: without specifying (string), field-is-string` type would have been inferred as boolean.

Note: we specified (string) as a type even if gchararray is the actual GType name as for convenience some well known types have been aliased or abbreviated.

To avoid specifying the type, you can give some hints to the “type system”. For example to specify a value as a double, you should add a decimal (ie. 1 is an int while 1.0 is a double).

Note: when a structure is serialized with gst_structure_to_string, all values are explicitly typed.

Some types have special delimiters:

• GstValueArray are inside curly brackets ({ and }). For example a-structure, array={1, 2, 3}
• Ranges are inside brackets ([ and ]). For example a-structure, range=[1, 6, 2] 1 being the min value, 6 the maximum and 2 the step. To specify a GST_TYPE_INT64_RANGE you need to explicitly specify it like: a-structure, a-int64-range=(gint64) [1, 5]
• GstValueList are inside “less and greater than” (< and >). For example `a-structure, list=<1, 2, 3>

Structures are delimited either by a null character \0 or a semicolon ; the latter allowing to store multiple structures in the same string (see Caps).

Quotes are used as “default” delimiters and can be used around any types that don’t use other delimiters (for example a-struct, i=(int)"1"). They are use to allow adding spaces or special characters (such as delimiters, semicolumns, etc..) inside strings and you can use backslashes \ to escape characters inside them, for example:

a-struct, special="\"{[(;)]}\" can be used inside quotes"

They also allow for nested structure, such as:

a-struct, nested=(GstStructure)"nested-struct, nested=true"

Since 1.20, nested structures and caps can be specified using brackets ([ and ]), for example:

a-struct, nested=[nested-struct, nested=true]

note: [to_str()][Self::to_str()] won’t use that syntax for backward compatibility reason, [serialize_full()][Self::serialize_full()] has been added for that purpose.

Implementations

impl Structure

pub fn builder(name: impl IntoGStr) -> Builder

pub fn new_empty(name: impl IntoGStr) -> Structure

Creates a new, empty Structure with the given name.

See gst_structure_set_name() for constraints on the name parameter.

Free-function: gst_structure_free

name

name of new structure

Returns

a new, empty Structure

pub fn from_iter( name: impl IntoGStr, iter: impl IntoIterator<Item = (impl IntoGStr, SendValue)>, ) -> Structure

Methods from Deref<Target = StructureRef>

pub fn as_ptr(&self) -> *const GstStructure

pub fn as_mut_ptr(&self) -> *mut GstStructure

pub fn get<'a, T: FromValue<'a>>( &'a self, name: impl IntoGStr, ) -> Result<T, GetError<<<T as FromValue<'a>>::Checker as ValueTypeChecker>::Error>>

pub fn get_optional<'a, T: FromValue<'a>>( &'a self, name: impl IntoGStr, ) -> Result<Option<T>, GetError<<<T as FromValue<'a>>::Checker as ValueTypeChecker>::Error>>

pub fn value( &self, name: impl IntoGStr, ) -> Result<&SendValue, GetError<Infallible>>

pub fn get_by_quark<'a, T: FromValue<'a>>( &'a self, name: Quark, ) -> Result<T, GetError<<<T as FromValue<'a>>::Checker as ValueTypeChecker>::Error>>

pub fn get_optional_by_quark<'a, T: FromValue<'a>>( &'a self, name: Quark, ) -> Result<Option<T>, GetError<<<T as FromValue<'a>>::Checker as ValueTypeChecker>::Error>>

pub fn value_by_quark( &self, name: Quark, ) -> Result<&SendValue, GetError<Infallible>>

pub fn set(&mut self, name: impl IntoGStr, value: impl Into<Value> + Send)

Sets field name to the given value value.

Overrides any default or previously defined value for name.

pub fn set_if( &mut self, name: impl IntoGStr, value: impl Into<Value> + Send, predicate: bool, )

Sets field name to the given inner value if value is Some.

This has no effect if the predicate evaluates to false, i.e. default or previous value for name is kept.

pub fn set_if_some( &mut self, name: impl IntoGStr, value: Option<impl Into<Value> + Send>, )

Sets field name to the given inner value if value is Some.

This has no effect if the value is None, i.e. default or previous value for name is kept.

pub fn set_from_iter<V: ValueType + Into<Value> + FromIterator<SendValue> + Send>( &mut self, name: impl IntoGStr, iter: impl IntoIterator<Item = impl ToSendValue>, )

Sets field name using the given ValueType V built from iter’s the Items.

Overrides any default or previously defined value for name.

pub fn set_if_not_empty<V: ValueType + Into<Value> + FromIterator<SendValue> + Send>( &mut self, name: impl IntoGStr, iter: impl IntoIterator<Item = impl ToSendValue>, )

Sets field name using the given ValueType V built from iter’s Items, if iter` is not empty.

This has no effect if iter is empty, i.e. previous value for name is unchanged.

pub fn set_value(&mut self, name: impl IntoGStr, value: SendValue)

Sets field name to the given value value.

Overrides any default or previously defined value for name.

pub fn set_value_if( &mut self, name: impl IntoGStr, value: SendValue, predicate: bool, )

Sets field name to the given inner value if value is Some.

This has no effect if the predicate evaluates to false, i.e. default or previous value for name is kept.

pub fn set_value_if_some( &mut self, name: impl IntoGStr, value: Option<SendValue>, )

Sets field name to the given inner value if value is Some.

This has no effect if the value is None, i.e. default or previous value for name is kept.

pub fn set_by_quark(&mut self, name: Quark, value: impl Into<Value> + Send)

pub fn set_by_quark_if_some( &mut self, name: Quark, value: Option<impl Into<Value> + Send>, )

pub fn set_value_by_quark(&mut self, name: Quark, value: SendValue)

pub fn set_value_by_quark_if_some( &mut self, name: Quark, value: Option<SendValue>, )

pub fn name<'a>(&self) -> &'a GStr

pub fn name_quark(&self) -> Quark

pub fn set_name(&mut self, name: impl IntoGStr)

pub fn set_name_if_some(&mut self, name: Option<impl IntoGStr>)

pub fn has_name(&self, name: &str) -> bool

pub fn has_field(&self, field: impl IntoGStr) -> bool

pub fn has_field_with_type(&self, field: impl IntoGStr, type_: Type) -> bool

pub fn has_field_by_quark(&self, field: Quark) -> bool

pub fn has_field_with_type_by_quark(&self, field: Quark, type_: Type) -> bool

pub fn remove_field(&mut self, field: impl IntoGStr)

pub fn remove_fields(&mut self, fields: impl IntoIterator<Item = impl IntoGStr>)

pub fn remove_all_fields(&mut self)

pub fn fields(&self) -> FieldIterator<'_>

pub fn iter(&self) -> Iter<'_>

pub fn nth_field_name<'a>(&self, idx: usize) -> Option<&'a GStr>

pub fn n_fields(&self) -> usize

pub fn len(&self) -> usize

pub fn is_empty(&self) -> bool

pub fn can_intersect(&self, other: &StructureRef) -> bool

pub fn intersect(&self, other: &StructureRef) -> Option<Structure>

pub fn is_subset(&self, superset: &StructureRef) -> bool

pub fn fixate(&mut self)

pub fn fixate_field(&mut self, name: impl IntoGStr) -> bool

pub fn fixate_field_bool(&mut self, name: impl IntoGStr, target: bool) -> bool

pub fn fixate_field_str( &mut self, name: impl IntoGStr, target: impl IntoGStr, ) -> bool

pub fn fixate_field_nearest_double( &mut self, name: impl IntoGStr, target: f64, ) -> bool

pub fn fixate_field_nearest_fraction( &mut self, name: impl IntoGStr, target: impl Into<Fraction>, ) -> bool

pub fn fixate_field_nearest_int( &mut self, name: impl IntoGStr, target: i32, ) -> bool

pub fn serialize(&self, flags: SerializeFlags) -> GString

pub fn serialize_strict( &self, flags: SerializeFlags, ) -> Result<GString, BoolError>

pub fn foreach<F: FnMut(Quark, &Value) -> ControlFlow<()>>( &self, func: F, ) -> bool

pub fn map_in_place<F: FnMut(Quark, &mut Value) -> ControlFlow<()>>( &mut self, func: F, ) -> bool

pub fn filter_map_in_place<F: FnMut(Quark, Value) -> Option<Value>>( &mut self, func: F, )

Trait Implementations

impl AsMut<StructureRef> for Structure

fn as_mut(&mut self) -> &mut StructureRef

Converts this type into a mutable reference of the (usually inferred) input type.

impl AsRef<StructureRef> for Structure

fn as_ref(&self) -> &StructureRef

Converts this type into a shared reference of the (usually inferred) input type.

impl Borrow<StructureRef> for Structure

fn borrow(&self) -> &StructureRef

Immutably borrows from an owned value.

impl BorrowMut<StructureRef> for Structure

fn borrow_mut(&mut self) -> &mut StructureRef

Mutably borrows from an owned value.

impl Clone for Structure

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Structure

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for Structure

type Target = StructureRef

The resulting type after dereferencing.

fn deref(&self) -> &StructureRef

Dereferences the value.

impl DerefMut for Structure

fn deref_mut(&mut self) -> &mut StructureRef

Mutably dereferences the value.

impl<'de> Deserialize<'de> for Structure

fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error>

Deserialize this value from the given Serde deserializer.

impl Display for Structure

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Drop for Structure

fn drop(&mut self)

Executes the destructor for this type.

impl Extend<Structure> for CapsRef

fn extend<T: IntoIterator<Item = Structure>>(&mut self, iter: T)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl From<Structure> for Caps

fn from(v: Structure) -> Caps

Converts to this type from the input type.

impl From<Structure> for Value

fn from(v: Structure) -> Value

Converts to this type from the input type.

impl FromGlibPtrBorrow<*const GstStructure> for Structure

unsafe fn from_glib_borrow(ptr: *const GstStructure) -> Borrowed<Self>

Safety

impl FromGlibPtrBorrow<*mut GstStructure> for Structure

unsafe fn from_glib_borrow(ptr: *mut GstStructure) -> Borrowed<Self>

Safety

impl FromGlibPtrFull<*const GstStructure> for Structure

unsafe fn from_glib_full(ptr: *const GstStructure) -> Self

Safety

impl FromGlibPtrFull<*mut GstStructure> for Structure

unsafe fn from_glib_full(ptr: *mut GstStructure) -> Self

Safety

impl FromGlibPtrNone<*const GstStructure> for Structure

unsafe fn from_glib_none(ptr: *const GstStructure) -> Self

Safety

impl FromGlibPtrNone<*mut GstStructure> for Structure

unsafe fn from_glib_none(ptr: *mut GstStructure) -> Self

Safety

impl FromIterator<Structure> for Caps

fn from_iter<T: IntoIterator<Item = Structure>>(iter: T) -> Self

Creates a value from an iterator.

impl FromStr for Structure

type Err = BoolError

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.

impl<'a> FromValue<'a> for Structure

type Checker = GenericValueTypeOrNoneChecker<Structure>

Value type checker.

unsafe fn from_value(value: &'a Value) -> Self

Get the contained value from a Value.

impl GlibPtrDefault for Structure

type GlibType = *mut GstStructure

impl IntoGlibPtr<*mut GstStructure> for Structure

unsafe fn into_glib_ptr(self) -> *mut GstStructure

Transfer: full.

impl PartialEq<Structure> for StructureRef

fn eq(&self, other: &Structure) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialEq<StructureRef> for Structure

fn eq(&self, other: &StructureRef) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialEq for Structure

fn eq(&self, other: &Structure) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for Structure

fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error>

Serialize this value into the given Serde serializer.

impl StaticType for Structure

fn static_type() -> Type

Returns the type identifier of Self.

impl<'a> ToGlibPtr<'a, *const GstStructure> for Structure

type Storage = PhantomData<&'a Structure>

fn to_glib_none(&'a self) -> Stash<'a, *const GstStructure, Self>

Transfer: none.

fn to_glib_full(&self) -> *const GstStructure

Transfer: full.

fn to_glib_container(&'a self) -> Stash<'a, P, Self>

Transfer: container.

impl<'a> ToGlibPtr<'a, *mut GstStructure> for Structure

type Storage = PhantomData<&'a Structure>

fn to_glib_none(&'a self) -> Stash<'a, *mut GstStructure, Self>

Transfer: none.

fn to_glib_full(&self) -> *mut GstStructure

Transfer: full.

fn to_glib_container(&'a self) -> Stash<'a, P, Self>

Transfer: container.

impl<'a> ToGlibPtrMut<'a, *mut GstStructure> for Structure

type Storage = PhantomData<&'a mut Structure>

fn to_glib_none_mut(&'a mut self) -> StashMut<'_, *mut GstStructure, Self>

Transfer: none.

impl ToValue for Structure

fn to_value(&self) -> Value

Convert a value to a Value.

fn value_type(&self) -> Type

Returns the type identifier of self.

impl ToValueOptional for Structure

fn to_value_optional(s: Option<&Self>) -> Value

Convert an Option to a Value.

impl ValueType for Structure

type Type = Structure

Type to get the Type from.

impl Eq for Structure

impl Send for Structure

impl Sync for Structure

impl TransparentPtrType for Structure

impl ValueTypeOptional for Structure